Utz Roedig

Wireless sensor networks are currently the subject of intense research and many prototype installations are currently investigated. These existing sensor network installations have in common that they are not considered time critical. No immediate action has to be undertaken as a response to the received data. However, many future application areas of wireless sensor networks such as plant automation and control, traffic management or medical applications require this feature. In such environments, data has to be transported reliable and in time through the sensor network. In other words, performance guarantees regarding a variety of network parameters are required. Due to the lack of appropriate models, components and protocols it is currently very difficult to construct and operate a wireless sensor network with a controlled performance. The goal of this work is to devise such models, components and protocols that allow us to operate a performance controlled sensor network.

Wireless Sensor Networks can only be employed in mission critical scenarios if secure communication can be provided. However, classical security mechanisms are difficult to use in the context of WSNs as specific requirements must be fulfilled. For example, security must be provided in an energy efficient way. The aim of this work is to devise suitable protocols, components and mechanisms for securing WSNs.

Communication in wireless sensor networks is mainly defined by the medium access control protocol that organises the access of multiple nodes to the shared medium; in such networks, the MAC protocol must be carefully designed to appropriately balance conflicting goals such as high throughput and low energy consumption. The design space for MAC protocols in wireless sensor networks is determined to a large extent by the capabilities of the communication transceivers used by the sensor nodes. However, current MAC protocols are not well matched to the capabilities of modern low-power transceivers. The aim of this work is therefore to investigate how the interaction between MAC protocols and low power transceivers can be improved to optimise communications in wireless sensor networks.

In many embedded system scenarios data has to be transmitted over long distances (several hundred meters). Examples are process control in refineries or vehicle-driver communication. Data rates are low, link quality is poor but high transmission reliability and energy efficiency is required. My work aims to define protocols for these scenarios.

Future embedded systems contain more than one processing unit. Classical operating systems designed to execute on a central processing unit (CPU) are an ill fit for upcoming multiprocessor platforms. It is my aim to develop operating system concepts that fit hardware layouts we will encounter in the future.

The aim of this work is to provide a multi-level infrastructure of interconnected testbeds of large-scale wireless sensor networks for research purposes, pursuing an interdisciplinary approach that integrates the aspects of hardware, software, algorithms, and data. This will demonstrate how heterogeneous small-scale devices and testbeds can be brought together to form well-organized, large-scale structures, rather than just some large network; it will allow research not only at a much larger scale, but also in different quality, due to heterogeneous structure and the ability to deal with dynamic scenarios, both in membership and location.